C13 amido substituted taxane derivatives and pharmaceutical compositions containing them

ABSTRACT

Taxane derivatives having an amino substituted C13 side chain.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation application based on U.S. Ser. No.08/953,889, filed Oct. 20, 1997, now U.S. Pat. No. 6,051,724, which is adivisional application of U.S. Ser. No. 08/462,112, filed Jun. 5, 1995,now U.S. Pat. No. 5,710,287, which is a continuation application of U.S.Ser. No. 08/094,566, filed Jul. 20, 1993, now abandoned, which is acontinuation-in-part application of U.S. Ser. No. 08/034,247 filed Mar.22, 1993, now U.S. Pat. No. 5,430,160, which is a continuation-in-partof U.S. Ser. No. 07/949,107, filed Sep. 22, 1992, now abandoned, whichis a continuation-in-part application of U.S. Ser. No. 07/863,849, filedApr. 6, 1992, now abandoned, which is a continuation-in-part applicationof U.S. Ser. No. 07/862,955, filed Apr. 3, 1992, now abandoned, which isa continuation-in-part of U.S. Ser. No. 07/763,805, filed Sep. 23, 1991,now abandoned. Said application Ser. No. 08/094,566 filed Jul. 20, 1993,now abandoned, is also a continuation-in-part application of U.S. Ser.No. 08/034,852, filed Mar. 22, 1993, now abandoned, which is acontinuation-in-part application of U.S. Ser. No. 07/862,819, filed Apr.3, 1992, now U.S. Pat. No. 5,227,400, which is a continuation-in-partapplication of U.S. Ser. No. 07/763,805, filed Mar. 22,1993, nowabandoned, filed Sep. 23, 1991, now abandoned. Said application Ser. No.08/034,852 is also a continuation in part application of U.S. Ser. No.07/975,723, filed Nov. 13, 1992, now U.S. Pat. No. 5,283,253, which is acontinuation-in-part of U.S. Ser. No. 07/949,107, filed Sep. 22, 1992,now abandoned, which is a continuation-in-part application of U.S. Ser.No. 07/863,849, filed Apr. 6, 1992, now abandoned, which is acontinuation-in-part application of U.S. Ser. No. 07/862,955, filed Apr.3, 1992, now abandoned, which is a continuation-in-part of U.S. Ser. No.07/763,805, filed Sep. 23, 1991, now abandoned.

This invention was made with Government support under NIH Grant#CA 42031and NIH Grant#CA 55131 awarded by the National Institutes of Health. TheGovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention is directed to novel taxanes which have utility asantileukemia and antitumor agents.

The taxane family of terpenes, of which taxol is a member, has attractedconsiderable interest in both the biological and chemical arts. Taxol isa promising cancer chemotherapeutic agent with a broad spectrum ofantileukemic and tumor-inhibiting activity. Taxol has a 2′R, 3′Sconfiguration and the following structural formula:

wherein Ac is acetyl. Because of this promising activity, taxol iscurrently undergoing clinical trials in both France and the UnitedStates.

Colin et al. reported in U.S. Pat. No. 4,814,470 that taxol derivativeshaving structural formula (2) below, have an activity significantlygreater than that of taxol (1).

R′ represents hydrogen or acetyl and one of R″ and R′″ representshydroxy and the other represents tert-butoxy-carbonylamino and theirstereoisomeric forms, and mixtures thereof. The compound of formula (2)in which R′ is hydrogen, R″ is hydroxy, R′″ is tert-butoxycarbonylaminohaving the 2′R, 3′S configuration is commonly referred to as taxotere.

Although taxol and taxotere are promising chemotherapeutic agents, theyare not universally effective. Accordingly, a need remains foradditional chemotherapeutic agents.

SUMMARY OF THE INVENTION

Among the objects of the present invention, therefore, is the provisionof novel taxane derivatives which are valuable antileukemia andantitumor agents.

Briefly, therefore, the present invention is directed to taxanederivatives having a C13 side chain which includes an amino substituent.In a preferred embodiment, the taxane derivative has a tricyclic ortetracyclic core and corresponds to the formula:

wherein

X₁ is —OX₆, —SX₇, or —NX₈X₉;

X₂ is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl;

X₃ and X₄ are independently hydrogen, alkyl, alkenyl, alkynyl, aryl, orheteroaryl;

X₅ is —CONX₈X₁₀;

X₆ is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, hydroxyprotecting group, or a functional group which increases the watersolubility of the taxane derivative;

X₇ is alkyl, alkenyl, alkynyl, aryl, heteroaryl, or sulfhydrylprotecting group;

X₈ is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, orheterosubstituted alkyl, alkenyl, alkynyl, aryl or heteroaryl;

X₁₀ is alkyl, alkenyl, alkynyl, aryl, heteroaryl, or heterosubstitutedalkyl, alkenyl, alkynyl, aryl or heteroaryl;

X₁₄ is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl;

R₁ is hydrogen, hydroxy, protected hydroxy or together with R₁₄ forms acarbonate;

R₂ is hydrogen, hydroxy, —OCOR₃₁ or together with R_(2a) forms an oxo;

R_(2a) is hydrogen or taken together with R₂ forms an oxo or;

R₄ is hydrogen, together with R_(4a) forms an oxo, oxirane or methylene,or together with R_(5a) and the carbon atoms to which they are attachedform an oxetane ring;

R_(4a) is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cyano,hydroxy, —OCOR₃₀, or together with R₄ forms an oxo, oxirane ormethylene;

R₅ is hydrogen or together with R_(5a) forms an oxo,

R_(5a) is hydrogen, hydroxy, protected hydroxy, acyloxy, together withR₅ forms an oxo, or together with R₄ and the carbon atoms to which theyare attached form an oxetane ring;

R₆ is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, hydroxy,protected hydroxy or together with R_(6a) forms an oxo;

R_(6a) is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl,hydroxy, protected hydroxy or together with R₆ forms an oxo;

R₇ is hydrogen or together with R_(7a) forms an oxo,

R_(7a) is hydrogen, halogen, protected hydroxy, —OR₂₈, or together withR₇ forms an oxo;

R₉ is hydrogen or together with R_(9a) forms an oxo,

R_(9a) is hydrogen, hydroxy, protected hydroxy, acyloxy, or togetherwith R₉ forms an oxo;

R₁₀ is hydrogen or together with R_(10a) forms an oxo,

R_(10a) is hydrogen, —OCOR₂₉, hydroxy, or protected hydroxy, or togetherwith R₁₀ forms an oxo;

R₁₄ is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, hydroxy,protected hydroxy or together with R₁ forms a carbonate;

R_(14a) is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl;

R₂₈ is hydrogen, acyl, hydroxy protecting group or a functional groupwhich increases the solubility of the taxane derivative; and

R₂₉, R₃₀, and R₃₁ are independently hydrogen, alkyl, alkenyl, alkynyl,monocyclic aryl or monocyclic heteroaryl.

Other objects and features of this invention will be in part apparentand in part pointed out hereinafter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein “Ar” means aryl; “Ph” means phenyl; “Ac” means acetyl;“Et” means ethyl; “R” means alkyl unless otherwise defined; “Bu” meansbutyl; “Pr” means propyl; “TES” means triethylsilyl; “TMS” meanstrimethylsilyl; “TPAP” means tetrapropylammonium perruthenate; “DMAP”means p-dimethylamino pyridine; “DMF” means dimethylformamide; “LDA”means lithium diisopropylamide; “LHMDS” means lithiumhexamethyldisilazide; “LAH” means lithium aluminum hydride; “Red-Al”means sodium bis(2-methoxyethoxy) aluminum hydride; “AIBN” meansazo-(bis)-isobutyronitrile; “10-DAB” means 10-desacetylbaccatin III; FARmeans 2-chloro-1,1,2-triflourotriethylamine; protected hydroxy means —ORwherein R is a hydroxy protecting group; sulfhydryl protecting group”includes, but is not limited to, hemithioacetals such as 1-ethoxyethyland methoxymethyl, thioesters, or thiocarbonates; “amine protectinggroup” includes, but is not limited to, carbamates, for example,2,2,2-trichloroethylcarbamate or tertbutylcarbamate; and “hydroxyprotecting group” includes, but is not limited to, ethers such asmethyl, t-butyl, benzyl, p-methoxybenzyl, p-nitrobenzyl, allyl, trityl,methoxymethyl, methoxyethoxymethyl, ethoxyethyl, tetrahydropyranyl,tetrahydrothiopyranyl, 2-methoxypropyl (“MOP”), and trialkylsilyl etherssuch as trimethylsilyl ether, triethylsilyl ether, dimethylarylsilylether, triisopropylsilyl ether and t-butyldimethylsilyl ether; esterssuch as benzoyl, acetyl, phenylacetyl, formyl, mono-, di-, andtrihaloacetyl such as chloroacetyl, dichloroacetyl, trichloroacetyl,trifluoroacetyl; and carbonates including but not limited to alkylcarbonates having from one to six carbon atoms such as methyl, ethyl,n-propyl, isopropyl, n-butyl, t-butyl; isobutyl, and n-pentyl; alkylcarbonates having from one to six carbon atoms and substituted with oneor more halogen atoms such as 2,2,2-trichloroethoxymethyl and2,2,2-trichloro-ethyl; alkenyl carbonates having from two to six carbonatoms such as vinyl and allyl; cycloalkyl carbonates having from threeto six carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl andcyclohexyl; and phenyl or benzyl carbonates optionally substituted onthe ring with one or more C₁₋₆ alkoxy, or nitro. Other hydroxyl,sulfhydryl and amine protecting groups may be found in “ProtectiveGroups in Organic Synthesis” by T. W. Greene, John Wiley and Sons, 1981.

The alkyl groups described herein, either alone or with the varioussubstituents defined herein are preferably lower alkyl containing fromone to six carbon atoms in the principal chain and up to 15 carbonatoms. They may be substituted, straight, branched chain or cyclic andinclude methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclopropyl,cyclopentyl, cyclohexyl and the like.

The alkenyl groups described herein, either alone or with the varioussubstituents defined herein are preferably lower alkenyl containing fromtwo to six carbon atoms in the principal chain and up to 15 carbonatoms. They may be substituted, straight or branched chain and includeethenyl, propenyl, isopropenyl, butenyl, isobutenyl, hexenyl, and thelike.

The alkynyl groups described herein, either alone or with the varioussubstituents defined herein are preferably lower alkynyl containing fromtwo to six carbon atoms in the principal chain and up to 15 carbonatoms. They may be substituted, straight or branched chain and includeethynyl, propynyl, butynyl, isobutynyl, hexynyl, and the like.

The aryl moieties described herein, either alone or with varioussubstituents, contain from 6 to 15 carbon atoms and include phenyl.Substituents include alkanoxy, protected hydroxy, halogen, alkyl, aryl,alkenyl, acyl, acyloxy, nitro, amino, amido, etc. Phenyl is the morepreferred aryl.

The heteroaryl moieties described herein, either alone or with varioussubstituents, contain from 5 to 15 atoms and include, furyl, thienyl,pyridyl and the like. Substituents include alkanoxy, protected hydroxy,halogen, alkyl, aryl, alkenyl, acyl, acyloxy, nitro, amino, and amido.

The acyloxy groups described herein contain alkyl, alkenyl, alkynyl,aryl or heteroaryl groups.

The substituents of the substituted alkyl, alkenyl, alkynyl, aryl, andheteroaryl groups and moieties described herein, may be alkyl, alkenyl,alkynyl, aryl, heteroaryl and/or may contain nitrogen, oxygen, sulfur,halogens and include, for example, lower alkoxy such as methoxy, ethoxy,butoxy, halogen such as chloro or fluoro, nitro, amino, and keto.

In accordance with the present invention, it has been discovered thatcompounds corresponding to structural formula 3 show remarkableproperties, in vitro, and are valuable antileukemia and antitumoragents. Their biological activity has been determined in vitro, usingtubulin assays according to the method of Parness et al., J. CellBiology, 91: 479-487 (1981) and human cancer cell lines, and iscomparable to that exhibited by taxol and taxotere.

In one embodiment of the present invention, the substituents of thecyclic nucleus of the taxane (other than the C13 substituent) correspondto the substituents present on baccatin III or 10-DAB. That is, R₁₄ andR_(14a) are hydrogen, R₁₀ is hydrogen, R_(10a) is hydroxy or acetoxy, R₉and R_(9a) together form an oxo, R₇ is hydrogen, R_(7a) is hydroxy, R₅is hydrogen, R_(5a) and R₄ and the carbons to which they are attachedform an oxetane ring, R_(4a) is acetoxy, R₂ is hydrogen, R_(2a) isbenzoyloxy, and R₁ is hydroxy. In other embodiments, the taxane has astructure which differs from that of taxol or taxotere with respect tothe C13 side chain and at least one other substituent. For example, R₁₄may be hydroxy, R₂ may be hydroxy or —OCOR₃₁ wherein R₃₁ is hydrogen,alkyl or selected from the group comprising

and Z is alkyl, hydroxy, alkoxy, halogen, or trifluoromethyl. R_(9a) maybe hydrogen and R₉ may be hydrogen or hydroxy, R_(7a) may be hydrogenand R₇ may be acetoxy or other acyloxy or halogen, or R₁₀ and R_(10a)may each be hydrogen or together form an oxo.

With respect to the C13 side-chain, in a preferred embodiment X₁ is —OH,X₂ is hydrogen, X₃ is alkyl, alkenyl, aryl or heteroaryl, X₄ ishydrogen, X₈ and X₁₀ are independently hydrogen or alkyl, and the taxanehas the 2′R, 3′S configuration. In a particularly preferred embodiment,X₃ is phenyl, furyl, thienyl, pyridyl, isobutenyl, isopropyl,cyclopropyl, n-butyl, t-butyl, cyclobutyl, cyclohexyl, amyl or thesubstituted analogs thereof, X₈ is hydrogen and X₁₀ is ethyl, propyl orbutyl.

Taxanes having the general formula 3 may be obtained by reacting aβ-lactam with alkoxides having the taxane tricyclic or tetracyclicnucleus and a C-13 metallic oxide substituent to form compounds having aβ-amido ester substituent at C-13. The β-lactams have the followingstructural formula:

wherein X₁-X₅ are as defined above.

The β-lactams can be prepared from readily available materials, as isillustrated in schemes A and B below:

reagents: (a) triethylamine, CH₂Cl₂, 25° C., 18 h; (b) 4 equiv cericammonium nitrate, CH₃CN, −10° C., 10 min; (c) KOH, THF, H₂O, 0° C., 30min, or pyrolidine, pyridine, 25° C., 3 h, (d) TESCl, pyridine, 25° C.,30 min or 2-methoxypropene toluene sulfonic acid (cat.), THF, 0° C., 2h; (e) n-butyllithium, THF, −78° C., 30 min; and an acyl chloride orchloroformate (X₅=—COX₁₀), sulfonyl chloride (X₅=—COSX₁₀) or isocyanate(X₅=—CONX₈X₁₀); (f) lithium diisopropyl amide, THF −78° C. to −50° C.;(g) lithium hexamethyldisilazide, THF −78° C. to 0° C.; (h) THF, −78° C.to 25° C., 12 h.

The starting materials are readily available. In scheme A, α-acetoxyacetyl chloride is prepared from glycolic acid, and, in the presence ofa tertiary amine, it cyclocondenses with imines prepared from aldehydesand p-methoxyaniline to give1-p-methoxyphenyl-3-acyloxy-4-arylazetidin-2-ones. The p-methoxyphenylgroup can be readily removed through oxidation with ceric ammoniumnitrate, and the acyloxy group can be hydrolyzed under standardconditions familiar to those experienced in the art to provide3-hydroxy-4-arylazetidin-2-ones. In Scheme B,ethyl-α-triethylsilyloxyacetate is readily prepared from glycolic acid.

In Schemes A and B, X₁ is preferably —OX₆ and X₆ is a hydroxy protectinggroup. Protecting groups such as 2-methoxypropyl (“MOP”), 1-ethoxyethyl(“EE”) are preferred, but a variety of other standard protecting groupssuch as the triethylsilyl group or other trialkyl (or aryl) silyl groupsmay be used. As noted above, additional hydroxy protecting groups andthe synthesis thereof may be found in “Protective groups in OrganicSynthesis” by T. W. Greene, John Wiley & Sons, 1981.

The racemic β-lactams may be resolved into the pure enantiomers prior toprotection by recrystallization of the corresponding2-methoxy-2-(trifluoromethyl) phenylacetic esters. However, the reactiondescribed hereinbelow in which the β-amido ester side chain is attachedhas the advantage of being highly diastereoselective, thus permittingthe use of a racemic mixture of side chain precursor.

The alkoxides having the tricyclic or tetracyclic taxane nucleus and aC-13 metallic oxide or ammonium oxide substituent have the followingstructural formula:

wherein R₁-R_(14a) are as previously defined and M comprises ammonium oris a metal optionally selected from the group comprising Group IA, GroupIIA and transition metals, and preferably, Li, Mg, Na, K or Ti. Mostpreferably, the alkoxide has the tetracyclic taxane nucleus andcorresponds to the structural formula:

wherein M, R₂, R_(4a), R₇, R_(7a), R₉, R_(9a), R₁₀, and R_(10a) are aspreviously defined.

The alkoxides can be prepared by reacting an alcohol having the taxanenucleus and a C-13 hydroxyl group with an organometallic compound in asuitable solvent. Most preferably, the alcohol is a protected baccatinIII, in particular, 7-O-triethylsilyl baccatin III (which can beobtained as described by Greene, et al. in JACS 110: 5917 (1988) or byother routes) or 7,10-bis-O-triethylsilyl baccatin III.

As reported in Greene et al., 10-deacetyl baccatin III is converted to7-O-triethylsilyl-10-deacetyl baccatin III according to the followingreaction scheme:

Under what is reported to be carefully optimized conditions, 10-deacetylbaccatin III is reacted with 20 equivalents of (C₂H₅)₃SiCl at 23° C.under an argon atmosphere for 20 hours in the presence of 50 ml ofpyridine/mmol of 10-deacetyl baccatin III to provide7-triethylsilyl-10-deacetyl baccatin III (4a) as a reaction product in84-86% yield after purification. The reaction product may thenoptionally be acetylated with 5 equivalents of CH₃COCl and 25 mL ofpyridine/mmol of 4a at 0° C. under an argon atmosphere for 48 hours toprovide 86% yield of 7-O-triethylsilyl baccatin III (4b). Greene, et al.in JACS 110, 5917 at 5918 (1988).

The 7-protected baccatin III (4b) is reacted with an organometalliccompound such as LHMDS in a solvent such as tetrahydrofuran (THF), toform the metal alkoxide 13-O-lithium-7-O-triethylsilyl baccatin III asshown in the following reaction scheme:

As shown in the following reaction scheme,13-O-lithium-7-O-triethylsilyl baccatin III reacts with a β-lactam inwhich X₁ is preferably —OX₆, (X₆ being a hydroxy protecting group) andX₂-X₅ are as previously defined to provide an intermediate in which theC-7 and C-2′hydroxyl groups are protected. The protecting groups arethen hydrolyzed under mild conditions so as not to disturb the esterlinkage or the taxane substituents.

Both the conversion of the alcohol to the alkoxide and the ultimatesynthesis of the taxane derivative can take place in the same reactionvessel. Preferably, the β-lactam is added to the reaction vessel afterformation therein of the alkoxide.

Compounds of formula 3 of the instant invention are useful forinhibiting tumor growth in animals including humans and are preferablyadministered in the form of a pharmaceutical composition comprising aneffective antitumor amount of compound of the instant invention incombination with a pharmaceutically acceptable carrier or diluent.

Antitumor compositions herein may be made up in any suitable formappropriate for desired use; e.g., oral, parenteral or topicaladministration. Examples of parenteral administration are intramuscular,intravenous, intraperitoneal, rectal and subcutaneous administration.

The diluent or carrier ingredients should not be such as to diminish thetherapeutic effects of the antitumor compounds.

Suitable dosage forms for oral use include tablets, dispersible powders,granules, capsules, suspensions, syrups, and elixirs. Inert diluents andcarriers for tablets include, for example, calcium carbonate, sodiumcarbonate, lactose and talc. Tablets may also contain granulating anddisintegrating agents such as starch and alginic acid, binding agentssuch as starch, gelatin and acacia, and lubricating agents such asmagnesium stearate, stearic acid and talc. Tablets may be uncoated ormay be coated by unknown techniques; e.g., to delay disintegration andabsorption. Inert diluents and carriers which may be used in capsulesinclude, for example, calcium carbonate, calcium phosphate and kaolin.Suspensions, syrups and elixirs may contain conventional excipients, forexample, methyl cellulose, tragacanth, sodium alginate; wetting agents,such as lecithin and polyoxyethylene stearate; and preservatives, e.g.,ethyl-p-hydroxybenzoate.

Dosage forms suitable for parenteral administration include solutions,suspensions, dispersions, emulsions and the like. They may also bemanufactured in the form of sterile solid compositions which can bedissolved or suspended in sterile injectable medium immediately beforeuse. They may contain suspending or dispersing agents known in the art.

The water solubility of compounds of formula (3) may be improved bymodification of the C2′and/or C7 substituents. For instance, watersolubility may be increased if X₁ is —OX₆ and R_(7a) is —OR₂₈, and X₆and R₂₈ are independently hydrogen or —COGCOR¹ wherein

G is ethylene, propylene, —CH═CH—, 1,2-cyclohexane, or 1,2-phenylene,

R¹=OH base, NR²R³, OR³, SR³, OCH₂CONR⁴R⁵, OH

R²=hydrogen, methyl

R³=(CH₂)_(n)NR⁶R⁷; (CH₂)_(n)N^(⊕)R⁶R⁷R⁸X^(⊖)

n=1 to 3

R⁴=hydrogen, lower alkyl containing 1 to 4 carbons

R⁵=hydrogen, lower alkyl containing 1 to 4 carbons, benzyl,hydroxyethyl, CH₂CO₂H, dimethylaminoethyl

R⁶R⁷=lower alkyl containing 1 or 2 carbons, benzyl or R⁶ and

R⁷ together with the nitrogen atom of NR⁶R⁷ form the following rings

R⁸=lower alkyl containing 1 or 2 carbons, benzyl

X^(⊖)=halide

base=NH₃, (HOC₂H₄)₃N, N(CH₃)₃, CH₃N(C₂H₄OH)₂, NH₂(CH₂)₆NH₂,N-methylglucamine, NaOH, KOH.

The preparation of compounds in which X₁ or X₂ is —COGCOR¹ is set forthin Haugwitz U.S. Pat. No. 4,942,184 which is incorporated herein byreference.

Alternatively, solubility may be increased when X₁ is —OX₆ and X₆ is aradical having the formula —COCX═CHX or —COX—CHX—CHX—SO₂O—M wherein X ishydrogen, alkyl or aryl and M is hydrogen, alkaline metal or an ammoniogroup as described in Kingston et al., U.S. Pat. No. 5,059,699(incorporated herein by reference).

Taxanes having alternative substituents may be prepared by selectivelyreducing the C9 keto substituent to yield the corresponding C9 β-hydroxyderivative. The reducing agent is preferably a borohydride and, mostpreferably, tetrabutylammoniumboro-hydride (Bu₄NBH₄) ortriacetoxyborohydride.

As illustrated in Reaction Scheme 1, the reaction of baccatin III withBu₄NBH₄ in methylene chloride yields 9-desoxo-9β-hydroxybaccatin III 5.After the C7 hydroxy group is protected with the triethylsilylprotecting group, for example, a suitable side chain may be attached to7-protected-9β-hydroxy derivative 6 as elsewhere described herein.Removal of the remaining protecting groups thus yields 9β-hydroxy-desoxotaxol or other 9β-hydroxytetracylic taxane having a C13 side chain.

Alternatively, the C13 hydroxy group of 7-protected-9β-hydroxyderivative 6 may be protected with trimethylsilyl or other protectinggroup which can be selectively removed relative to the C7 hydroxyprotecting group as illustrated in Reaction Scheme 2, to enable furtherselective manipulation of the various substituents of the taxane. Forexample, reaction of 7,13-protected-9β-hydroxy derivative 7 with KHcauses the acetate group to migrate from C10 to C9 and the hydroxy groupto migratefrom C9 to C10, thereby yielding 10-desacetyl derivative 8.Protection of the C10 hydroxy group of 10-desacetyl derivative 8 withtriethylsilyl yields derivative 9. Selective removal of the C13 hydroxyprotecting group from derivative 9 yields derivative 10 to which asuitable side chain may be attached as described above.

As shown in Reaction Scheme 3, 10-oxo derivative 11 can be provided byoxidation of 10-desacetyl derivative 8. Thereafter, the C13 hydroxyprotecting group can be selectively removed followed by attachment of aside chain as described above to yield 9-acetoxy-10-oxo-taxol or other9-acetoxy-10-oxotetracylic taxanes having a C13 side chain.Alternatively, the C9 acetate group can be selectively removed byreduction of 10-oxo derivative 11 with a reducing agent such as samariumdiiodide to yield 9-desoxo-10-oxo derivative 12 from which the C13hydroxy protecting group can be selectively removed followed byattachment of a side chain as described above to yield9-desoxo-10-oxo-taxol or other 9-desoxo-10-oxotetracylic taxanes havinga C13 side chain.

Reaction Scheme 4 illustrates a reaction in which 10-DAB is reduced toyield pentaol 13. The C7 and C10 hydroxyl groups of pentaol 13 can thenbe selectively protected with the triethylsilyl or another protectinggroup to produce triol 14 to which a C13 side chain can be attached asdescribed above or, alternatively, after further modification of thetetracylic substituents.

Taxanes having C9 and/or C10 acyloxy substituents other than acetate canbe prepared using 10-DAB as a starting material as illustrated inReaction Scheme 5. Reaction of 10-DAB with triethylsilyl chloride inpyridine yields 7-protected 10-DAB 15. The C10 hydroxy substituent of7-protected 10-DAB 15 may then be readily acylated with any standardacylating agent to yield derivative 16 having a new C10 acyloxysubstituent. Selective reduction of the C9 keto substituent ofderivative 16 yields 9β-hydroxy derivative 17 to which a C13 side chainmay be attached. Alternatively, the C10 and C9 groups can be caused tomigrate as set forth in Reaction Scheme 2, above.

Taxanes having alternative C2 and/or C4 esters can be prepared usingbaccatin III and 10-DAB as starting materials. The C2 and/or C4 estersof baccatin III and 10-DAB can be selectively reduced to thecorresponding alcohol(s) using reducing agents such as LAH or Red-Al,and new esters can thereafter be substituted using standard acylatingagents such as anhydrides and acid chlorides in combination with anamine such as pyridine, triethylamine, DMAP, or diisopropyl ethyl amine.Alternatively, the C2 and/or C4 alcohols may be converted to new C2and/or C4 esters through formation of the corresponding alkoxide bytreatment of the alcohol with a suitable base such as LDA followed by anacylating agent such as an acid chloride.

Baccatin III and 10-DAB analogs having different substituents at C2and/or C4 can be prepared as set forth in Reaction Schemes 6-10. Tosimplify the description, 10-DAB is used as the starting material. Itshould be understood, however, that baccatin III derivatives or analogsmay be produced using the same series of reactions (except for theprotection of the C10 hydroxy group) by simply replacing 10-DAB withbaccatin III as the starting material. 9-desoxo derivatives of thebaccatin III and 10-DAB analogs having different substituents at C2and/or C4 can then be prepared by reducing the C9 keto substituent ofthese analogs and carrying out the other reactions described above.

In Reaction Scheme 6, protected 10-DAB 3 is converted to the triol 18with lithium aluminum hydride. Triol 18 is then converted to thecorresponding C4 ester using Cl₂CO in pyridine followed by anucleophilic agent (e.g., Grignard reagents or alkyllithium reagents).

Deprotonation of triol 18 with LDA followed by introduction of an acidchloride selectively gives the C4 ester. For example, when acetylchloride was used, triol 18 was converted to 1,2 diol 4 as set forth inReaction Scheme

Triol 18 can also readily be converted to the 1,2 carbonate 19.Acetylation of carbonate 19 under vigorous standard conditions providescarbonate 21 as described in Reaction Scheme 8; addition ofalkyllithiums or Grignard reagents to carbonate 19 provides the C2 esterhaving a free hydroxyl group at C4 as set forth in Reaction Scheme 6.

As set forth in Reaction Scheme 9, other C4 substituents can be providedby reacting carbonate 19 with an acid chloride and a tertiary amine toyield carbonate 22 which is then reacted with alkyllithiums or Grignardreagents to provide 10-DAB derivatives having new substituents at C2.

Alternatively, baccatin III may be used as a starting material andreacted as shown in Reaction Scheme 10. After being protected at C7 andC13, baccatin III is reduced with LAH to produce 1,2,4,10 tetraol 24.Tetraol 24 is converted to carbonate 25 using Cl₂CO and pyridine, andcarbonate 25 is acylated at C10 with an acid chloride and pyridine toproduce carbonate 26 (as shown) or with acetic anhydride and pyridine(not shown). Acetylation of carbonate 26 under vigorous standardconditions provides carbonate 27 which is then reacted with alkyllithiums to provide the baccatin III derivatives having new substituentsat C2 and C10.

10-desacetoxy derivatives of baccatin III and 10-desoxy derivatives of10-DAB may be prepared by reacting baccatin III or 10-DAB (or theirderivatives) with samarium diiodide. Reaction between the tetracyclictaxane having a C10 leaving group and samarium diiodide may be carriedout at 0° C. in a solvent such as tetrahydrofuran. Advantageously, thesamarium diiodide selectively abstracts the C10 leaving group; C13 sidechains and other substituents on the tetracyclic nucleus remainundisturbed. Thereafter, the C9 keto substituent may be reduced toprovide the corresponding 9-desoxo-9β-hydroxy-10-desacetyoxy or10-desoxy derivatives as otherwise described herein.

C7 dihydro and other C7 substituted taxanes can be prepared as set forthin Reaction Schemes 11, 12 and 12a.

As shown in Reaction Scheme 12, Baccatin III may be converted into7-fluoro baccatin III by treatment with FAR at room temperature in THFsolution. Other baccatin derivatives with a free C7 hydroxyl groupbehave similarly. Alternatively, 7-chloro baccatin III can be preparedby treatment of baccatin III with methane sulfonyl chloride andtriethylamine in methylene chloride solution containing an excess oftriethylamine hydrochloride.

Taxanes having C7 acyloxy substituents can be prepared as set forth inReaction Scheme 12a, 7,13-protected 10-oxo-derivative 11 is converted toits corresponding C13 alkoxide by selectively removing the C13protecting group and replacing it with a metal such as lithium. Thealkoxide is then reacted with a β-lactam or other side chain precursor.Subsequent hydrolysis of the C7 protecting groups causes a migration ofthe C7 hydroxy substituent to C10, migration of the C10 oxo substituentto C9, and migration of the C9 acyloxy substituent to C7.

A wide variety of tricyclic taxanes are naturally occurring, and throughmanipulations analogous to those described herein, an appropriate sidechain can be attached to the C13 oxygen of these substances.Alternatively, as shown in Reaction Scheme 13, 7-O-triethylsilylbaccatin III can be converted to a tricyclic taxane through the actionof trimethyloxonium tetrafluoroborate in methylene chloride solution.The product diol then reacts with lead tetraacetate to provide thecorresponding C4 ketone.

Recently a hydroxylated taxane (14-hydroxy-10-deacetylbaccatin III) hasbeen discovered in an extract of yew needles (C&EN, p 36-37, Apr. 12,1993). Derivatives of this hydroxylated taxane having the various C2,C4, etc. functional groups described above may also be prepared by usingthis hydroxylated taxane. In addition, the C14 hydroxy group togetherwith the C1 hydroxy group of 10-DAB can be converted to a 1,2-carbonateas described in C&EN or it may be converted to a variety of esters orother functional groups as otherwise described herein in connection withthe C2, C4, C9 and C10 substituents.

The following examples are provided to more fully illustrate theinvention.

EXAMPLE 1

Preparation of N-debenzoyl-N-(dimethylcarbamyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.174 mL of a 1.63 M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-(dimethylcarbamyl)-3-triethyl-silyloxy-4-phenylazetidin-2-one (249mg, 0.715 mmol) in 1 mL of THF was added dropwise to the mixture. Thesolution was warmed to 0° C. and kept at that temperature for 1 h before1 mL of a 10% solution of AcOH in THF was added. The mixture waspartitioned between saturated aqueous NaHCO₃ and 60/40 ethylacetate/hexane. Evaporation of the organic layer gave a residue whichwas purified by filtration through silica gel to give 150 mg of amixture containing (2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(dimethylcarbamyl) taxol and a smallamount of the (2′S,3′R) isomer.

To a solution of 150 mg (0.143 mmol) of the mixture obtained from theprevious reaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0°C. was added 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C.for 3 h, then at 25° C. for 13 h, and partitioned between saturatedaqueous sodium bicarbonate and ethyl acetate. Evaporation of the ethylacetate solution gave 117 mg of material which was purified byfiltration through silica gel followed by recrystallization fromacetonitrile/water to give 105 mg (90%) ofN-debenzoyl-N-(dimethylcarbamyl) taxol.

m.p.179-181° C.; [α]²⁵Na −54.36° (c 0.00195 , CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.1 Hz, 2H, benzoate ortho),7.64-7.20 (m, 8H, aromatic), 6.27 (s, 1H, H10), 6.19 (m, 1H, H13), 5.67(d, J=7.1 Hz, 1H, H2β), 5.40 (dd, J=7.7, 3.3 Hz, 1H,H3′),5.20 (d, J=7.7Hz, 1H,NH), 4.94 (dd, J=9.8, 2.2 Hz, 1H, H5), 4.66 (d, J=3.3 Hz, 1H,H2′), 4.40 (m, 1H, H7), 4.29 (d, J=8.2 Hz, 1H, H20α), 4.17 (d, J=8.2 Hz,1H, H20β), 3.77 (d, J=7.1 Hz, 1H, H3), 2.89 (s,6H, dimethyl carbamyl),2.53 (m, 1H, H6α), 2.46 (br s, 1H, 7 OH), 2.36 (s, 3H, 4Ac), 2.29 (m,2H, H14), 2.23 (s, 3H, 10Ac), 1.87 (m, 1H, H6β), 1.79 (br s, 3H, Me18),1.67 (s, 3H, Me19), 1.25 (s, 3H, Me17), 1.14 (s, 3H, Me16).

EXAMPLE 2

Preparation of N-debenzoyl-N-(diethylcarbamyl) Taxol

To a solution of 7-triethylsilyl baccatin III (200 mg, 0.286 mmol) in 2mL of THF at −45° C. was added dropwise 0.174 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-(diethylcarbamyl)-3-triethyl-silyloxy-4-phenylazetidin-2-one (538mg, 1.43 mmol) in 2 mL of THF was added dropwise to the mixture. Thesolution was warmed to 0° C. and kept at that temperature for 1 h before1 mL of a 10% solution of AcOH in THF was added. The mixture waspartitioned between saturated aqueous NaHCO₃ and 60/40 ethylacetate/hexane. Evaporation of the organic layer gave a residue whichwas purified by filtration through silica gel to give 308 mg of amixture containing (2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(diethylcarbamyl) taxol and a smallamount of the (2′S,3′R) isomer.

To a solution of 308 mg (0.286 mmol) of the mixture obtained from theprevious reaction in 18 mL of acetonitrile and 0.93 mL of pyridine at 0°C. was added 2.8 mL of 48% aqueous HF. The mixture was stirred at 0° C.for 3 h, then at 25° C. for 13 h, and partitioned between saturatedaqueous sodium bicarbonate and ethyl acetate. Evaporation of the ethylacetate solution gave 243 mg of material which was purified by flashchromatography to give 216 mg (89%) of N-debenzoyl-N-(diethylcarbamyl)taxol, which was recrystallized from methanol/water.

m.p.185-187° C.; [α]²⁵Na −68.4° (c 0.00995 , CHCl₃).

²H NMR (CDCl_(3, 300) MHz) δ8.10 (d, J=7.1 Hz, 2H, benzoate ortho),7.63-7.27 (m, 8H, aromatic), 6.27 (s, 1H, H10), 6.18 (dd, J=8.3, 8.3 Hz,1H, H13), 5.66 (d, J=7.1 Hz, 1H, H2β), 5.46 (d, J=8.2 Hz, 1H,H3′),5.24(d, J=8.2 Hz, 1H,NH), 4.94 (d, J=7.7, 2.2 Hz, 1H, H5), 4.67 (d, J=3.8Hz, 1H, H2′), 4.40 (m, 1H, H7), 4.28 (d, J=8.8 Hz, 1H, H20α), 4.16 (d,J=8.2 Hz, 1H, H20β), 3.77 (d, J=7.1 Hz, 1H, H3), 3.22 (m,4H, diethylcarbamyl), 2.53 (m, 1H, H6α), 2.37 (s, 3H, 4Ac), 2.31 (m, 2H, H14), 2.23(s, 3H, 10Ac), 1.88 (m, 1H, H6β), 1.81 (br s, 3H, Me18), 1.66 (s, 3H,Me19), 1.24 (s, 3H, Me17), 1.13 (s, 3H, Me16), 1.08 ( t, 6H, diethylcarbamyl).

EXAMPLE 3

Preparation of N-debenzoyl-N-(diphenylcarbamyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-(diphenylcarbamyl)-3-tri-ethylsilyloxy-4-phenylazetidin-2-one (676mg, 1.43 mmol) in 1 mL of THF was added dropwise to the mixture. Thesolution was warmed to 0° C. and kept at that temperature for 1 h before1 mL of a 10% solution of AcOH in THF was added. The mixture waspartitioned between saturated aqueous NaHCO₃ and 60/40 ethylacetate/hexane. Evaporation of the organic layer gave a residue whichwas purified by filtration through silica gel to give 168 mg of amixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(diphenylcarbamyl) taxoland a small amount of the (2′S,3′R) isomer.

To a solution of 168 mg (0.143 mmol) of the mixture obtained from theprevious reaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0°C. was added 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C.for 3 h, then at 25° C. for 13 h, and partitioned between saturatedaqueous sodium bicarbonate and ethyl acetate. Evaporation of the ethylacetate solution gave 135 mg of material which was purified by flashchromatography to give 121 mg (89%) of N-debenzoyl-N-(diphenylcarbamyl)taxol, which was recrystallized from methanol/water.

m.p.159-162° C.; [α]²⁵Na −89.0° (c 0.0103 , CHCl₃).

²H NMR (CDCl₃, 300 MHz) δ8.05 (d, J=7.7 Hz, 2H, benzoate ortho),7.57-7.14 (m, 18H, aromatic), 6.29 (s, 1H, H10), 6.23 (m,1H, H13), 5.67(d, J=6.6 Hz, 1H, H2β), 5.51 (dd, J=9.3, 2.2 Hz, 1H,H3′), 5.36 (d, J=9.3Hz, 1H,NH), 4.94 (d, J=8.2 Hz, 1H, H5), 4.63 (dd, J=5.5, 2.2 Hz, 1H,H2′), 4.42 (m, 1H, H7), 4.25 (d, J=8.8 Hz, 1H, H20α), 4.18 (d, J=8.2 Hz,1H, H20β), 3.77 (d, J=7.1 Hz, 1H, H3), 3.38 (d,1H, 2′OH), 2.53 (m, 1H,H6α), 2.47 ( d, J=3.9 Hz, 1H, 70H), 2.39 (s, 3H, 4Ac), 2.24 (s, 3H,10Ac), 1.87 (m, 1H, H6β), 1.84 (br s, 3H, Me18), 1.70 ( s, 1H, 1OH ),1.67 (s, 3H, Me19), 1.28 (s, 3H, Me17), 1.15 (s, 3H, Me16).

EXAMPLE 4

Preparation of N-debenzoyl-N-(N-ethylcarbamoyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-ethyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-phenylazetidin-2-one (327 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 165mg of a mixture containing (2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-ethyl-N-thiophenyl-carbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 165 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 133 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 109.0 mg (93%) ofN-debenzoyl-N-(N-ethylcarbamoyl) taxol.

m.p. 167-168° C.; [α]²⁵Na −59° (c 0.002, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.10 (d, J=7.1 Hz, 2H, benzoate ortho),7.64-7.29(m, 8H, aromatic), 6.27(s, 1H, H10), 6.18 (dd, J=8.8, 8.8.8 Hz,1H, H13), 5.66(d, J=6.1 Hz, 1H, H2β), 5.34(br ,2H, H3′,Et-NH), 4.93(d,J=7.7 Hz, 1H, H5), 4.63(d, J=2.75 Hz,1H, H2′), 4.38 (m, 1H, H7), 4.28(d, J=8.2 Hz, 1H, H20α), 4.16 (d, J=8.2 Hz, 1H, H20β), 3.76 (d, J=7.1Hz, 1H, H3), 3.11(m, 2H, Me-CH2), 2.51 (m, 1H, H6α), 2.42(m, 1H, 7OH),2.35(s, 3H, 4Ac), 2.25 (m, 2H, H14s), 2.23(s, 3H, 10Ac), 1.85 (m, 1H,H6β), 1.80(br s, 3H, Me18), 1.70 (s, 1H, 1OH), 1.66 (s, 3H, Me19), 1.23(s, 3H, Me17), 1.13(s, 3H, Me16), 0.82 (dd, J=7.1, 14.1 Hz,3H,CH3).

EXAMPLE 5

Preparation of N-debenzoyl-N-(N-n-propylcarbamoyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-n-propyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-phenylazetidin-2-one (336 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 167mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-n-propyl-N-thiophenyl-carbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 167 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 135 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 111.0 mg (93%) ofN-debenzoyl-N-(N-n-propylcarbamoyl) taxol.

m.p. 167-168° C.; [α]²⁵ _(Na)−58° (c 0.002, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.12 (d, J=7.1 Hz, 2H, benzoate ortho),7.63-7.31(m, 8H, aromatic), 6.29(s, 1H, H10), 6.22 (dd, J=7.8, 7.8 Hz,1H, H13), 5.68(d, J=6.1 Hz, 1H, H2β), 5.38(br s, 1H, H3′), 5.30(br s,1H, NH), 4.95(d,J=9.6 Hz, 1H, H5), 4.80(br s,1H,NH), 4.66(d, J=3.2Hz,1H, H2′), 4.41 (m, 1H, H7), 4.30 (d, J=8.7 Hz, 1H, H20α), 4.19 (d,J=8.7 Hz, 1H, H20β), 3.79 (d, J=6.8 Hz, 1H, H3), 3.05(m, 2H, Et-CH2),2.54 (m, 1H, H6α), 2.44(m, 1H, 7OH), 2.39 (s, 3H, 4Ac), 2.28 (m, 2H,H14s), 2.25(s, 3H, 10Ac), 1.88(m, 1H, H6β), 1.86(br s, 3H, Me18), 1.69(s, 3H, Me19), 1.68 (s, 1H, 1OH), 1.43(dd, J=7.1, 14.8 Hz, 2H, Me CH2),1.27 (s, 3H, Me17), 1.16(s,3H, Me16), 0.82(dd, J=7.1, 14.1 Hz, 3H, CH3).

EXAMPLE 6

Preparation of N-debenzoyl-N-(t-butylcarbamoyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-t-butyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-phenylazetidin-2-one (346 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 169mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-t-butyl-N-thiophenyl-carbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 169 mg of the mixture obtained from the previousreaction in 4 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 1.2 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 24 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 121 mg of material which was purified by plug filtrationand recrystallization from methanol/water to give 115 mg (95%) ofN-debenzoyl-N-(t-butylcarbamoyl) taxol.

m.p. 164-165° C.; [α]²⁵ _(Na)−68° (c 0.0053, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.1 Hz, 2H, benzoate ortho),7.50-7.26(m, 8H, aromatic), 6.28(s, 1H, H10), 6.15 (dd, J=8.2,8.2 Hz,1H, H13), 5.66(d, J=7.1 Hz, 1H, H2β), 5.31(br s, 2H, H3′,NH),4.93(d,J=7.7 Hz, 1H, H5), 4.61(d, J=2.2 Hz, 1H, H2′), 4.35 (m, 1H, H7),4.28 (d, J=8.2 Hz, 1H, H20α), 4.16 (d, J=8.2 Hz, 1H, H20β), 3.76 (d,J=7.1 Hz, 1H, H3), 2.45 (m, 1H, H6α), 2.39(m, 1H, 7OH), 2.37 (s, 3H,4Ac), 2.36 (m, 2H, H14s), 2.22(s, 3H, 10Ac), 1.89(m, 1H, H6β), 1.82(brs, 3H, Me18), 1.66 (s, 3H, Me19), 1.65 (s, 1H, 1OH), 1.23 (s, 3H, Me17),1.20(s, 9H, t-butyl), 1.13(s,3H, Me16).

EXAMPLE 7

Preparation of N-debenzoyl-N-(N-cyclohexylcarbamoyl) taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-cyclohexyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-phenylazetidin-2-one (365 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 173mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-cyclohexyl-N-thiophenyl-carbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 173 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 140 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 117 mg (93%) ofN-debenzoyl-N-(N-cyclohexylcarbamoyl) taxol.

m.p. 167-168° C.; [α]²⁵ _(Na)−55 (c 0.002, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.10(d, J=7.1 Hz, 2H, benzoate ortho),7.62-7.24 (m, 8 H, aromatic), 6.27 (s, 1H, H10), 6.17 (dd, J=8.8, 8.8Hz, 1H, H13), 5.65(d, J=7.1 Hz, 1H, H2), 5.43(d, J=8.25 Hz, 1H,cycloheyl-NH), 5.33(dd, J=8.2,3.3 Hz, 1H, H3′), 4.92(d, J=8.2 Hz, 1H,H5), 4.72(br, 1H,NH), 4.62(d, J=3.3 Hz,1H, H2′), 4.37 (m, 1H, H7), 4.25(d, J=8.2 Hz, 1H, H20α), 4.16 (d, J=8.2 Hz, 1H, H20β), 3.75 (d, J=7.1Hz, 1H, H3), 3.37(m,1H, Cyclohexyl-CH), 2.45 (m, 1H, H6α), 2.35(m, 1H,7OH), 2.37(s, 3H, 4Ac), 2.21 (s, 3H, 10Ac), 2.19(m, 2H, H14), 1.83(m,1H, H6β), 1.81(br s, 3H, Me18), 1.75 (s, 3H, Me19), 1.70(s, 1H, 1OH),1.23 (s, 3H, Me17), 1.12(s,3H, Me16), 1.06-0.99(m, 10 H,cyclohexyl).

EXAMPLE 8

Preparation of N-debenzoyl-N-(N-phenylcarbamoyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)-amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-phenylthio-N-phenylcarbamoyl)-3-triethylsilyloxy-4-phenylazetidin-2-one (360 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 172mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-phenylthio-N-phenyl-carbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 172 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 139 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 115 mg (93%) of N-debenzoyl-N-(N-phenylcarbamoyl)taxol.

m.p. 166-167° C.; [α]²⁵ _(Na−)55 (c 0.0023, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11(d, J=7.1 Hz, 2H, benzoate ortho), 7.60-6.9(m, 13H, aromatic), 6.70(s, 1H, NH), 6.27 (s, 1H, H10), 6.24 (dd, J=8.2,8.2 Hz, 1H, H13), 5.91(d, J=7.7 Hz, NH), 5.72-5.66(m, 2H, H2,NH)),5.50(d, J=8.2 Hz, 1H, H3′), 4.95(d, J=7.1 Hz, 1H, H5), 4.69 (d, J=2.75Hz,1H, H2′), 4.38 (m, 1H, H7), 4.29 (d, J=8.2 Hz, 1H, H20α), 4.19 (d,J=8.2 Hz, 1H, H20β), 3.79 (d, J=7.1 Hz, 1H, H3), 2.54 (m, 1H, H6α),2.45(m, 1H, 7OH), 2.40 (s, 3H, 4Ac), 2.29(m, 2H, H14), 2.22 (s, 3H,10Ac), 1.85(m, 1H, H6β), 1.82(br s, 3H, Me18), 1.64 (s, 3H, Me19), 1.63(s, 1H, 1OH), 1.23 (s, 3H, Me17), 1.13(s,3H, Me16).

EXAMPLE 9

Preparation of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N-methyl-N-phenylcarbamoyl)Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-(N-methyl-N-phenylcarbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (286 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 157mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N-methyl-N-phenylcarbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 157 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 125 mg of material which was purified by flashchromatography to give 112 mg (90%) of31′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N-methyl-N-phenylcarbamoyl)taxol, which was recrystallized from methanol/water.

m.p. 176-177° C.; [α]²⁵ _(Na)−71.0° (c 0.520, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.12 (d, J=7.5 Hz, 2H, benzoate ortho), 7.61(m, 1H, benzoate, para), 7.50 (t, J=7.5 Hz, 2H, benzoate, meta), 7.36(m, 5H, phenyl), 7.24 (br s, 1H, furyl), 6.32 (br s, 2H, H10, furyl),6.26 (t, J=8.7 Hz, 1H, H13), 6.14 (d, J=3.3 Hz, 1H, furyl), 5.69 (d,J=7.2 Hz, 1H, H2β), 5.50 (dd, J=9.0, 2.1 Hz, H3′), 5.01 (d, J=9.0 Hz,NH), 4.96 (dd, J=8.5, 1.2 Hz, 1H, H5), 4.66 (br s, 1H, H2′), 4.43 (m,1H, H7), 4.30 (d, J=8.1 Hz, 1H, H20α), 4.18 (d, J=8.1 Hz, 1H, H20β),3.82 (d, J=7.2 Hz, 1H, H3), 3.52 (br s, 1H, 2′OH), 3.18 (s, 3H,N-methyl), 2.55 (m, 1H, H6α), 2.45 (m, 1H, 7OH), 2.40 (s, 3H, 4Ac), 2.36(m, 2H, H14), 2.25 (s, 3H, 10Ac), 1.87 (s, 3H, Me18), 1.83 (m, 1H, H6β),1.77 (s, 1H, 1OH), 1.68 (s, 3H, Me19), 1.29 (s, 3H, Me17), 1.16 (s, 3H,Me16).

EXAMPLE 10

Preparation of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N,N-dimethylcarbamoyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-N,N-dimethylcarbamoyl-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (242 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for i1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 148mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N,N-dimethylcarbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 148 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 117 mg of material which was purified by flashchromatography to give 98 mg (84%) of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(N,N-dimethylcarbamoyl) taxol,which was recrystallized from methanol/water.

m.p. 153-154° C.; [α]²⁵ _(Na)−69.1° (c 0.800, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.8 Hz, 2H, benzoate ortho), 7.61(m, 1H, benzoate, para), 7.49 (t, J=7.8 Hz, 2H, benzoate, meta), 7.41(br s, 1H, furyl), 6.36 (m, 1H, furyl), 6.33 (d, J=2.7 Hz, 1H, furyl),6.29 (s, 1H, H10), 6.23 (t, J=8.7, 1H, H13), 5.67 (d, J=6.9 Hz, 1H,H2β), 5.51 (dd, J=8.7, 2.4 Hz, 1H, H3′), 5.15 (d, J=8.7 Hz, 1H NH), 4.94(d, J=9.9 Hz, 1H, H5), 4.71 (br s, 1H, H2′), 4.42 (m, 1H, H7), 4.29 (d,J=8.4 Hz, 1H, H20α), 4.17 (d, J=8.4 Hz, 1H, H20β), 3.93 (m, 1H, 2′OH),3.80 (d, J=6.9 Hz, 1H, H3), 2.89 (s, 6H, dimethylcarbamoyl), 2.54 (m,1H, H6α), 2.46 (m, 1H, 7OH), 2.39 (s, 3H, 4Ac), 2.31 (m, 2H, H14), 2.24(s, 3H, 10Ac), 1.86 (s, 3H, Me18), 1.83 (m, 1H, H6β), 1.68 (s, 3H,Me19), 1.65 (s, 1H, 1OH), 1.26 (s, 3H, Me17), 1.15 (s, 3H, Me16).

EXAMPLE 11

Preparation of 3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(diethylcarbamyl)Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-diethylcarbamyl-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (262mg, 0.715 mmol) in 1 mL of THF was added dropwise to the mixture. Thesolution was warmed to 0° C. and kept at that temperature for 1 h before1 mL of a lot solution of AcOH in THF was added. The mixture waspartitioned between saturated aqueous NaHCO₃ and 60/40 ethylacetate/hexane. Evaporation of the organic layer gave a residue whichwas purified by filtration through silica gel to give 153 mg of amixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-diethylcarbamyltaxol and a small amount of the (2′S,3′R) isomer.

To a solution of 153 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 120 mg of material which was purified by flashchromatography to give 108 mg (90%) of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-diethylcarbamyl taxol, which wasrecrystallized from methanol/water.

m.p. 175-177° C.; [α]²⁵ _(Na)−69.3° (c 1.000, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.13 (d, J=7.2 Hz, 2H, benzoate ortho), 7.61(m, 1H, benzoate, para), 7.51 (t, J=7.2 Hz, 2H, benzoate, meta), 7.43(d, J=1.2 Hz, 1H, furyl), 6.38 (dd, J=3.0, 1.2 Hz, 1H, furyl), 6.32 (d,J=3.0 Hz, 1H, furyl), 6.31 (s, 1H, H10), 6.23 (t, J=8.7 Hz, 1H, H13),5.69 (d, J=7.2 Hz, 1H, H2β), 5.57 (dd, J=8.7, 2.7 Hz, 1H, H3′), 5.11 (d,J=8.7, NH), 4.96 (dd, J=9.9, 2.1 Hz, 1H, H5), 4.73 (d, J=2.7 Hz, 1H,H2′), 4.43 (m, 1H, H7), 4.31 (d, J=8.7 Hz, 1H, H20α), 4.18 (d, J=8.7 Hz,1H, H20β), 3.84 (d, J=7.2 Hz, 1H, H3), 3.81 (d, J=2.7 Hz, 2′OH), 3.22(m, 4H, diethylcarbamoyl), 2.56 (m, 1H, H6α), 2.46 (d, J=4.5 Hz, 7OH),2.42 (s, 3H, 4Ac), 2.32 (m, 2H, H14), 2.25 (s, 3H, 10Ac), 1.92 (m, 1H,H6β), 1.87 (s, 3H, Me18), 1.83 (s, 1H, 1OH), 1.69 (s, 3H, Me19), 1.27(s, 3H, Me17), 1.16 (s, 3H, Me16), 0.84 (t, J=7.2, 3H, butyl), 1.10 (t,J=7.2, 6H, diethylcarbamoyl).

EXAMPLE 12

Preparation of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(diphenylcarbamyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-diphenylcarbamyl-3-triethylsilyloxy-4-(2-furyl) azetidin-2-one(331 mg, 0.715 mmol) in 1 mL of THF was added dropwise to the mixture.The solution was warmed to 0° C. and kept at that temperature for 1 hbefore 1 mL of a 10% solution of AcOH in THF was added. The mixture waspartitioned between saturated aqueous NaHCO₃ and 60/40 ethylacetate/hexane. Evaporation of the organic layer gave a residue whichwas purified by filtration through silica gel to give 166 mg of amixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-diphenylcarbamyltaxol and a small amount of the (2′S,3′R) isomer.

To a solution of 166 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 134 mg of material which was purified by flashchromatography to give 122 mg (91%) of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-diphenylcarbamyl taxol, whichwas recrystallized from methanol/water.

m.p. 157-158° C.; [α]²⁵ _(Na)−88.5° (c 0.470, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.05 (d, J=7.2 Hz, 2H, benzoate ortho), 7.53(m, 1H, benzoate, para), 7.41 (t, J=7.2 Hz, 2H, benzoate, meta), 7.24(m, 11H, diphenylcarbamoyl, furyl), 6.36 (dd, J=3.3, 2.4 Hz, 1H, furyl),6.32 (s, 1H, H10), 6.27 (t, J=5.1 Hz, 1H, H13), 6.17 (d, J=3.3 Hz, 1H,furyl) 5.68 (d, J=6.6 Hz, 1H, H2β), 5.58 (d, J=9.2 Hz, 1H, H3′), 5.22(d, J=9.2 Hz, 1H, NH), 4.95 (d, J=7.8 Hz, 1H, H5), 4.72 (br s, 1H, H2′),4.42 (m, 1H, H7), 4.28 (d, J=9.0 Hz, 1H, H20α), 4.19 (d, J=9.0 Hz, 1H,H20β), 3.81 (d, J=6.6 Hz, 1H, H3), 3.29 (br s, 2′OH), 2.53 (m, 2H, H6α,7OH), 2.38 (s, 3H, 4Ac), 2.29 (m, 2H, H14), 2.25 (s, 3H, 10Ac), 1.92 (s,3H, Me18), 1.88 (m, 1H, H6β), 1.68 (s, 3H, Me19), 1.62 (s, 1H, 1OH),1.28 (s, 3H, Me17), 1.16 (s, 3H, Me16).

EXAMPLE 13

Preparation of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(4-morpholinocarbonyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.087 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution ofcis-1-(4-morpholinocarbonyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (272 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 155mg of a mixture containing(2′R,3′S)-2′,7-(bis)-triethylsilyl-3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(4-morpolinocarbonyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 155 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 122 mg of material which was purified by flashchromatography to give 105 mg (86%) of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(4-morpholinocarbonyl) taxol,which was recrystallized from methanol/water.

m.p. 175-176° C.; [α]²⁵ _(Na)−59.2° (c 0.500, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.2 Hz, 2H, benzoate ortho), 7.61(m, 1H, benzoate, para), 7.49 (t, J=7.2 Hz, 2H, benzoate, meta), 7.41(d, J=1.2 Hz, 1H, furyl), 6.38 (dd, J=3.3, 1.2 Hz, 1H, furyl), 6.32 (d,J=3.3 Hz, 1H, furyl), 6.29 (s, 1H, H10), 6.23 (t, J=8.7 Hz, 1H, H13),5.67 (d, J=6.6 Hz, 1H, H2β), 5.55 (dd, J=8.7, 2.7 Hz, 1H, H3′), 5.23 (d,J=8.7 Hz, 1H, NH), 4.95 (d, J=9.3 Hz, 1H, H5), 4.71 (d, J=2.7 Hz, 1H,H2′), 4.41 (m, 1H, H7), 4.25 (d, J=8.7 Hz, 1H, H20α), 4.17 (d, J=8.7 Hz,1H, H20β), 3.80 (d, J=6.6 Hz, 1H, H3), 3.67 (m, 1H, 2′OH), 3.62 (t,J=4.8 Hz, 4H, morpholine), 3.31 (t, J=4.8 Hz, 4H, morpholine), 2.54 (m,2H, H6α, 7OH), 2.39 (s, 3H, 4Ac), 2.31 (m, 2H, H14), 2.24 (s, 3H, 10Ac),1.86 (s, 3H, Me18), 1.83 (m, 1H, H6β),1.77 (br s, 1OH), 1.67 (s, 3H,Me19), 1.26 (s, 3H, Me17), 1.15 (s, 3H, Me16).

EXAMPLE 14

Preparation of 3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(ethylcarbamoyl)Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(ethylthiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (319 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 164mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′(2-furyl)-N-debenzoyl-N-(ethylcarbamoyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 164 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 131 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h and was then dilutedwith ethyl acetate and washed with saturated NaHCO₃. The solvent wasremoved and the residue was purified by plug filtration andrecrystallization from methanol/water to give 112.0 mg (93%) of3′-desphenyl-3′-(2-furyl)-N-debenzoyl-N-(ethylcarbamoyl) taxol.

m.p. 178-179° C.; [α]²⁵ _(Na)−60.5° (c 0.003, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=8.1 Hz, 2H, benzoate ortho),7.60-7.30 (m, 4H, aromatic,furyl), 6.36-6.29(m, 3H, furyl, H10), 6.19(dd, J=8.8, 8.8 Hz, 1H, H13), 5.67(d, J=7.1 Hz, 1H, H2β), 5.46(br s, 1H,H3′), 5.33(br s, 1H, NH), 4.93(d, J=7.7 Hz, 1H, H5), 4.72(d, J=2.2Hz,1H, H2′), 4.39 (m, 1H, H7), 4.28 (d, J=8.8 Hz, 1H, H20α), 4.17 (d,J=8.8 Hz, 1H, H20β), 3.79 (d, J=7.1 Hz, 1H, H3), 3.1(m, 2H, Me-CH2),2.62(br, 1H, 7OH), 2.44 (m, 1H, H6α), 2.38(s, 3H, 4Ac), 2.33 (m, 2H,H14s), 2.23(s, 3H, 10Ac), 1.86(m, 1H, H6β), 1.85(br s, 3H, Me18), 1.67(s, 3H, Me19), 1.66 (s, 1H, 1OH), 1.24 (s, 3H, Me17), 1.14(s,3H, Me16),1.049(dd,J=7.2, 7.2 Hz, 3H, CH3).

EXAMPLE 15

Preparation ofN-debenzoyl-N-(N-n-propylcarbamoyl)-3′-desphenyl-3′-(2-furyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-n-propyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (344 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 171mg of a mixture containing(2′R,3′S)-2′,7-(bis)-triethylsilyl-N-debenzoyl-N-(N-n-propyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-furyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 171 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 138 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 114.0 mg (93%) ofN-debenzoyl-N-(N-n-propylcarbamoyl)-3′-desphenyl-3′-(2-furyl) taxol.

m.p. 176-177° C.; [α]²⁵ _(Na)−59° (c 0.002, CHCl₃). ¹H NMR (CDCl₃, 300MHz) δ8.14 (d, J=8.1 Hz, 2H, benzoate ortho), 7.47-7.24 (m, 4H,aromatic), 6.21-6.13(m, 3H, furyl, H10), 6.15 (dd, J=8.8, 8.8 Hz, 1H,H13), 5.52(d, J=7.1 Hz, 1H, H2β), 5.33(br s, 1H, H3′), 5.10(br s, 1H,NH), 4.79(d, J=7.7 Hz, 1H, H5), 4.57(d, J=3.3 Hz,1H, H2′), 4.25 (m, 1H,H7), 4.19 (d, J=8.2 Hz, 1H, H20α), 4.12 (d, J=8.2 Hz, 1H, H20β), 3.65(d, J=6.6.Hz, 1H, H3), 2.89(m, 2H, Et-CH2), 2.45 (m, 1H, H6α), 2.40(m,1H, 7OH), 2.24 (s, 3H, 4Ac), 2.16 (m, 2H, H14s), 2.18(s, 3H, 10Ac),1.84(m, 1H, H6β), 1.82(br s, 3H, Me18), 1.67 (s, 3H, Me19), 1.66 (s, 1H,1OH), 1.39(dd, J=7.1, 14.8 Hz, 2H, Me CH2) 1.23 (s, 3H, Me17),1.14(s,3H, Me16), 0.79 (dd,J=7.1, 14.1 Hz, 3H, CH3).

EXAMPLE 16

Preparation ofN-desbenzoyl-N-(isopropylcarbamoyl)-3′-desphenyl-3′-(2-furyl) Taxol

To a solution of 7-O-triethylsilyl baccatin III (100 mg, 0.143 mmol) in1 mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solutionof lithium bis(trimethylsilyl)-amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(isopropyl-(phenylthio)-carbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (329 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 166mg of a mixture containing(2′R,3′S)-2′,7-(bis)-O-triethylsilyl-N-desbenzoyl-N-(isopropyl-(phenyl-thio)-carbamoyl)-3′-desphenyl-3′-(2-furyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 166 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 133 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate and washed with saturated aqueous NaHCO₃. The solvent wasremoved and the residue was purified by plug filtration andrecrystallization from methanol/water to give 114.0 mg (93%) ofN-desbenzoyl-N-(isopropylcarbamoyl)-3′-desphenyl-3′-(2-furyl) taxol.

m.p. 176-177 C; [α]²⁵ _(Na)−58.5° (c 0.004, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.12(d, J=8.1 Hz, 2H, benzoate ortho),7.52-7.24 (m, 4H, aromatic,furyl), 6.36-6.29(m, 3H, furyl, H10), 6.22(dd, J=8.8, 8.8 Hz, 1H, H13), 5.67(d, J=7.1 Hz, 1H, H2β), 5.47(br s, 1H,H3′), 5.21(br s, 1H, NH), 4.94(d, J=7.6 Hz, 1H, H5), 4.72(d, J=2.2Hz,1H, H2′), 4.31 (m, 1H, H7), 4.29 (d, J=8.8 Hz, 1H, H20α), 4.17 (d,J=8.8 Hz, 1H, H20β), 3.79 (d, J=7.1 Hz, 1H, H3), 3.72(m, 2H, N-CH),2.54(br, 1H, 7OH), 2.44 (m, 1H, H6α), 2.40(s, 3H, 4Ac), 2.33 (m, 2H,H14s), 2.23(s, 3H, 10Ac), 1.94(m, 1H, H6β), 1.86(br s, 3H, Me18), 1.67(s, 3H, Me19), 1.66 (s, 1H, 1OH), 1.23 (s, 3H, Me17), 1.14(s,3H, Me16),1.05(d, J=10.8 Hz, 6H, CH3).

EXAMPLE 17

Preparation of N-debenzoyl-N-(t-butylcarbamoyl)-3-desphenyl-3′-(2-furyl)Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-t-butyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (339 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 168mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-t-butyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-furyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 168 mg of the mixture obtained from the previousreaction in 4 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 1.2 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 24 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 119 mg of material which was purified by plug filtrationand recrystallization from methanol/water to give 114 mg (95%) ofN-debenzoyl-N-(t-butylcarbamoyl)-3′-desphenyl-3′-(2-furyl) taxol.

m.p. 161-162° C.; [α]²⁵ _(Na)−65° (c 0.0028, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.1 Hz, 2H, benzoate ortho),7.53-7.40(m, 4H, aromatic, furyl), 6.36-6.25(m, 3H, furyl, H10), 6.22(dd, J=8.1, 8.1 Hz, 1H, H13), 5.68(d, J=7.1 Hz, 1H, H2β), 5.47(dd,J=8.8,2,2 Hz, H3′), 4.96(d,J=8.8 Hz, 1H, H5), 4.84(d, J=9.3 Hz, 1H, NH),4.71(dd, J=5.5, 2.75 Hz, 1H, H2′), 4.42 (m, 1H, H7), 4.33(br s, 1H, NH),4.30 (d, J=8.2 Hz, 1H, H20α), 4.18 (d, J=8.2 Hz, 1H, H20β), 3.81 (d,J=6.6 Hz, 1H, H3),3.55(d, J=8.2 Hz, 1H, C2′OH), 2.45 (m, 1H, H6α),2.43(m, 1H, 7OH), 2.41 (s, 3H, 4Ac), 2.38 (m, 2H, H14s), 2.24(s, 3H,10Ac), 1.88(br s, 3H, Me18), 1.82(m, 1H, H6β), 1.70 (s, 1H, 1OH),1.68(s, 3H, Me19), 1.25 (s, 3H, Me17), 1.24(s, 9H,t-butyl), 1.15(s,3H,Me16).

EXAMPLE 18

Preparation ofN-debenzoyl-N-(N-phenylcarbamoyl)3′-desphenyl-3′-(2-furyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-phenyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-furyl)azetidin-2-one (354 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 171mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-phenyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-furyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 171 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 138 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 114.5 mg (93%) ofN-debenzoyl-N-(N-phenylcarbamoyl)-3′-desphenyl-3′-(2-furyl) taxol.

m.p. 165-166° C.; [α]²⁵ _(Na)−57° (c 0.0021, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.1 Hz, 2H, benzoate ortho),7.60-6.5 (m, 9H, phenyl furyl aromatic), 6.41-6.20 (m, 4H,furyl,H10,H13), 5.93 (d, J=9.3 Hz, ArNH), 5.68(d, J=7.1 Hz, H2β),5.60(d, J=8.6 Hz, 1H, H3′), 4.93(d, J=7.7 Hz, 1H, H5), 4.78(d, J=2.2Hz,1H, H2′), 4.40 (m, 1H, H7), 4.30 (d, J=8.8 Hz, 1H, H20α), 4.19 (d,J=8.8 Hz, 1H, H20β), 3.80 (d, J=6.6 Hz,1H, H3), 2.53 (m, 1H, H6α),2.40(m, 1H, 7OH), 2.39 (s, 3H, 4Ac), 2.33 (m, 2H, H14), 2.19 (s, 3H,10Ac), 1.91(m, 1H, H6β), 1.86(br s, 3H, Me18), 1.68 (s, 3H, Me19), 1.66(s, 1H, 1OH), 1.20 (s, 3H, Me17), 1.13(s,3H, Me16).

EXAMPLE 19

Preparation of3′-desphenyl-3′-(2-thienyl)-N-debenzoyl-N-(diethylcarbamyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.174 mL of a 1.63M solution ofnBuLi in hexane. After 0.5 h at −45° C., a solution of cis-1-(diethylcarbamyl)-3-triethylsilyloxy-4-(2-thienyl) azetidin-2-one (273 mg, 0.715mmol) in 1 mL of THF was added dropwise to the mixture. The solution waswarmed to 0° C. and kept at that temperature for 1 h before 1 mL of a10% solution of AcOH in THF was added. The mixture was partitionedbetween saturated aqueous NaHCO₃ and 60/40 ethyl acetate/hexane.Evaporation of the organic layer gave a residue which was purified byfiltration through silica gel to give 155 mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-3′-desphenyl-3′-(2-thienyl)-N-debenzoyl-N-(diethylcarbamyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 155 mg (0.143 mmol) of the mixture obtained from theprevious reaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0°C. was added 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C.for 3 h, then at 25° C. for 13 h, and partitioned between saturatedaqueous sodium bicarbonate and ethyl acetate. Evaporation of the ethylacetate solution gave 122 mg of material which was purified byfiltration through silica gel followed by recrystallization frommethanol/water to give 114 mg (93%) of3′-desphenyl-3′-(2-thienyl)-N-debenzoyl-N-(diethylcarbamyl) taxol.

m.p.149-151° C.; [α]²⁵ _(Na)−66.6° (c 0.00975 , CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.12 (d, J=7.1 Hz, 2H, benzoate ortho),7.64-6.99 (m, 6H, aromatic), 6.28 (s, 1H, H10), 6.23 (m, 1H, H13), 5.70(m, 2H, H3′& H2β), 5.19 (d, J=8.8 Hz, 1H,NH), 4.95 (d, J=7.7 Hz, 1H,H5), 4.68 (br s, 1H, H2′), 4.41 (m, 1H, H7), 4.30 (d, J=8.2 Hz, 1H,H20α), 4.19 (d, J=8.2 Hz, 1H, H20β), 3.81 (d, J=7.1 Hz, 1H, H3), 3.20(m,4H, diethyl carbamyl), 2.53 (m, 1H, H6α), 2.40 (s, 3H, 4Ac), 2.31 (m,2H, H14), 2.23 (s, 3H, 10Ac), 1.88 (m, 1H, H6β), 1.82 (br s, 3H, Me18),1.67 (s, 3H, Me19), 1.25 (s, 3H, Me17), 1.14 (s, 3H, Me16), 1.07 (t, 6H,diethyl carbamyl).

EXAMPLE 20

Preparation ofN-debenzoyl-N-(N-n-propylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-n-propyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-thienyl)azetidin-2-one (355 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 171mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-n-propyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-thienyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 171 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 140 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 114.5 mg (93%) ofN-debenzoyl-N-(N-n-propylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) taxol.

m.p. 163-164° C.; [α]²⁵ _(Na)−51° C. (c 0.0027, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.2 Hz, 2H, benzoate ortho),7.60-7.49 (m, 3H, aromatic), 7.2-6.7(m, 3H, thienyl) 6.28 (s, 1H, H10),6.20 (dd, J=8.7, 8.7 Hz, 1H, H13), 5.66(m, 2H, H3′, H2β), 5.34(d,J=9.3Hz,1H, Pr—NH), 4.93(d, J=9.3 Hz, 1H, H5), 4.64(d, J=2.75 Hz,1H, H2′),4.38 (m, 1H, H7), 4.29 (d, J=8.2 Hz, 1H, H20α), 4.20 (d, J=8.2 Hz, 1H,H20β), 3.78 (d, J=7.1 Hz, 1H, H3), 3.02(m, 2H,Et-CH2), 2.45 (m, 1H,H6α), 2.40(m, 1H, 7OH), 2.38 (s, 3H, 4Ac), 2.31 (m, 2H, H14), 2.23 (s,3H, 10Ac), 1.85(m, 1H, H6β), 1.83(br s, 3H, Me18), 1.67 (s, 3H, Me19),1.66 (s, 1H, 1OH), 1.39(dd, J=7.1, 14.8 Hz, 2H, Me CH2), 1.23 (s, 3H,Me17), 1.14(s,3H, Me16),0.79(dd,J=7.1, 14.1,3H,CH3).

EXAMPLE 21

Preparation ofN-debenzoyl-N-(t-butylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg0.143 mmol) in 1 mLof THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-t-butyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-thienyl)azetidin-2-one (350 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 170mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-t-butyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-thienyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 170 mg of the mixture obtained from the previousreaction in 4 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 1.2 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 24 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 122 mg of material which was purified by plug filtrationand recrystallization from methanol/water to give 115 mg (95%) ofN-debenzoyl-N-(t-butylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) taxol.

m.p. 168-169° C.; [α]²⁵ _(Na)−70 (c 0.002, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.7 Hz, 2H, benzoate ortho),7.53-7.40(m, 3H, aromatic), 7.21-6.90(m, 3H, thienyl), 6.29(s, 1H, H10),6.20 (dd, J=9.3,9.3 Hz, 1H, H13), 5.65(m, 2H, H3′, H2β) 5.12(br s,1H,NH), 4.93(d,J=7.9 Hz, 1H, H5), 4.64(d, 2.2 Hz,1H, H2′), 4.39 (m, 1H,H7), 4.31 (d, J=8.2 Hz, 1H, H20α), 4.18 (d, J=8.2 Hz, 1H, H20β), 3.97(d, J=7.1 Hz, 1H, H3), 2.46 (m, 1H, H6α), 2.43(m, 1H, 7OH), 2.39 (s, 3H,4Ac), 2.34(m, 2H, H14s), 2.23(s, 3H, 10Ac), 1.85(br s, 3H, Me18),1.83(m, 1H, H6β), 1.71 (s, 1H, 1OH), 1.67(s, 3H, Me19), 1.24 (s, 3H,Me17), 1.22(s, 9H, t-butyl), 1.14(s, 3H, Me16).

EXAMPLE 22

Preparation ofN-debenzoyl-N-(N-phenylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) Taxol

To a solution of 7-triethylsilyl baccatin III (100 mg, 0.143 mmol) in 1mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solution oflithium bis(trimethylsilyl)amide in THF. After 0.5 h at −45° C., asolution ofcis-1-(N-phenyl-N-thiophenylcarbamoyl)-3-triethylsilyloxy-4-(2-thienyl)azetidin-2-one (365 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 173mg of a mixture containing(2′R,3′S)-2′,7-(bis)triethylsilyl-N-debenzoyl-N-(N-phenyl-N-thiophenyl-carbamoyl)-3′-desphenyl-3′-(2-thienyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 173 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 140 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room.temperature for 3 h, diluted with ethylacetate, and washed with saturated NaHCO₃. The solvent was removed andthe residue was purified by plug filtration and recrystallization frommethanol/water to give 10 114.5 mg (93%) ofN-debenzoyl-N-(N-phenylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) taxol.

m.p. 175-177° C.;[α]²⁵ _(Na)−41° (c 0.002, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.12 (d, J=7.1 Hz, 2H, benzoate ortho),7.60-6.9 (m, 11H, phenyl thienyl aromatic), 6.28 (s, 1H, H10), 6.23 (dd,J=8.2, 8.2 Hz, 1H, H13), 5.91(d, J=7.7 Hz, NH), 5.76(d, J=8.2 Hz, 1H,H3′), 5.67(d, J=7.1 Hz,1H, H2β), 4.93(d, J=9.3, Hz, 1H, H5), 4.69 (d,J=2.2 Hz,1H, H2′), 4.38 (m, 1H, H7), 4.29 (d, J=8.8 Hz, 1H, H20α), 4.19(d, J=8.8 Hz, 1H, H20β), 3.79 (d, J=7.1 Hz, 1H, H3), 2.45 (m, 1H, H6α),2.42(m, 1H, 7OH), 2.39 (s, 3H, 4Ac), 2.30 (m, 2H, H14), , 2.20 (s, 3H,10Ac), 1.82(m, 1H, H6β), 1.81(br s, 3H, Me18), 1.67 (s, 3H, Me19), 1.66(s, 1H, 1OH), 1.20 (s, 3H, Me17), 1.1(s,3H, Me16).

EXAMPLE 23

Preparation ofN-desbenzoyl-N-(benzylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) Taxol

To a solution of 7-O-triethylsilyl baccatin III (100 mg, 0.143 mmol) in1 mL of THF at −45° C. was added dropwise 0.157 mL of a 1.00 M solutionof lithium bis(trimethylsilyl)-amide in THF. After 0.5 h at −45° C., asolution ofcis-1-benzyl-(phenylthio)-carbamoyl)-3-triethylsilyloxy-4-thienylazetidin-2-one (362 mg, 0.715 mmol) in 1 mL of THF was added dropwise tothe mixture. The solution was warmed to 0° C. and kept at thattemperature for 1 h before 1 mL of a 10% solution of AcOH in THF wasadded. The mixture was partitioned between saturated aqueous NaHCO₃ and60/40 ethyl acetate/hexane. Evaporation of the organic layer gave aresidue which was purified by filtration through silica gel to give 173mg of a mixture containing(2′R,3′S)-2′,7-(bis)-O-triethylsilyl-N-desbenzoyl-N-(benzyl-(phenyl-thio)-carbamoyl)-3′-desphenyl-3′-(2-thienyl)taxol and a small amount of the (2′S,3′R) isomer.

To a solution of 173 mg of the mixture obtained from the previousreaction in 6 mL of acetonitrile and 0.3 mL of pyridine at 0° C. wasadded 0.9 mL of 48% aqueous HF. The mixture was stirred at 0° C. for 3h, then at 25° C. for 13 h, and partitioned between saturated aqueoussodium bicarbonate and ethyl acetate. Evaporation of the ethyl acetatesolution gave 139 mg of material which was treated with2-mercapto-pyridine (80 mg, 0.72 mmol) in 2 mL of dichloromethane. Themixture was stirred at room temperature for 3 h, diluted with ethylacetate and washed with saturated aqueous NaHCO₃. The solvent wasremoved and the residue was purified by plug filtration andrecrystallization from methanol/water to give 118.0 mg (95%) ofN-desbenzoyl-N-(benzylcarbamoyl)-3′-desphenyl-3′-(2-thienyl) taxol.

m.p. 165-166° C.; [α]²⁵ _(Na)−63.5° (c 0.006, CHCl₃).

¹H NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.1 Hz, 2H, benzoate ortho),7.58-6.99(m, 11H, aromatic,thienyl), 6.26(s, 1H, H10), 6.22 (dd, J=8.8,8.8 Hz, 1H, H13), 5.70(m, 2H, H2β, H 3′), 5.26(br s ,1H, NH), 4.91(d,J=8.1 Hz, 1H, H5), 4.62(d, J=2.5 Hz,1H, H2′), 4.39-4.17 (m, 5H,H7,benzyl,H20′s), 3.75 (d, J=8.1 Hz, 1H, H3), 2.51(m, 1H, H6α), 2.42(m,1H, 7OH), 2.39(s, 3H, 4Ac), 2.34 (m, 2H, H14s), 2.24(s, 3H, 10Ac),1.86(m, 1H, H6β), 1.81(br s, 3H, Me18), 1.69(s, 1H, 1OH), 1.67(s, 3H,Me19), 1.23(s, 3H, Me17), 1.13(s, 3H, Me16).

EXAMPLE 24

The taxanes of the preceding examples were evaluated in in vitrocytotoxicity activity against human colon carcinoma cells HCT-116.Cytotoxicity was assessed in HCT116 human colon carcinoma cells by XTT(2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazoliumhydroxide) assay (Scudiero et al, “Evaluation of a solubletetrazolium/formazan assay for cell growth and drug sensitivity inculture using human and other tumor cell lines”, Cancer Res.48:4827-4833, 1988). Cells were plated at 4000 cells/well in 96 wellmicrotiter plates and 24 hours later drugs were added and serialdiluted. The cells were incubated at 37° C. for 72 hours at which timethe tetrazolium dye, XTT, was added. A dehydrogenase enzyme in livecells reduces the XTT to a form that absorbs light at 450 nm which canbe quantitated spectrophotometrically. The greater the absorbance thegreater the number of live cells. The results are expressed as an IC₅₀which is the drug concentration required to inhibit cell proliferation(i.e. absorbance at 450 nm) to 50% of that of untreated control cells.

Except for compounds 34-1 (Example 3), 45-4 (Example 4) and 38-3(Example 12), all compounds had an IC₅₀ value of less than 0.1,indicating that they are cytotoxically active. Compound 34-1 had an IC₅₀of at least 0.082, 45-4 had an IC₅₀ of at least 0.06 and 38-3 had anIC₅₀ value of at least 0.078.

We claim:
 1. A taxane having the 2′R, 3′S configuration andcorresponding to the structure

wherein X₁ is —OX₆, —SX₇, or —NX₈X₉; X₂ is hydrogen, alkyl, alkenyl,alkynyl, aryl, or heteroaryl; X₃ and X₄ are independently hydrogen,alkyl, alkenyl, alkynyl, aryl, or heteroaryl; X₅ is —CONX₈X₁₀; X₆ ishydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, hydroxy protectinggroup, or functional group which increases the water solubility of thetaxane derivative; X₇ is alkyl, alkenyl, alkynyl, aryl, heteroaryl, orsulfhydryl protecting group; X₈ is hydrogen, alkyl, alkenyl, alkynyl,aryl, heteroaryl, or heterosubstituted alkyl, alkenyl, alkynyl, aryl orheteroaryl; X₉ is an amino protecting group; X₁₀ is alkyl, alkenyl,alkynyl, aryl, heteroaryl, or heterosubstituted alkyl, alkenylalkynyl,aryl or heteroaryl; X₁₁ is alkyl, alkenyl, alkynyl, aryl,heteroaryl, —OX₁₀, or —NX₈X₁₄; X₁₄ is hydrogen, alkyl, alkenyl, alkynyl,aryl, or heteroaryl; R₁ is hydrogen, hydroxy, protected hydroxy ortogether with R₁₄ forms a carbonate; R₂ is hydrogen, hydroxy, —OCOR₃₁ ortother with R_(2a) forms an oxo; R_(2a) is hydrogen or together with R₂forms an oxo; R₄ is hydrogen, together with R_(4a) forms an oxo, oxiraneor methylene, or together with R_(5a) and the carbon atoms to which theyare attached form an oxetane ring; R_(4a) is hydrogen, alkyl, alkenyl,alkynyl, aryl, heteroaryl, cyano, hydroxy, —OCOR₃₀, or together with R₄forms an oxo, oxirane or methylene; R₅ is hydrogen or together withR_(5a) forms an oxo, R_(5a) is hydrogen, hydroxy, protected hydroxy,acyloxy, together with R₅ forms an oxo, or together with R₄ and thecarbon atoms to which they are attached form an oxetane ring; R₆ ishydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, hydroxy,protected hydroxy or together with R_(6a) forms an oxo; R_(6a) ishydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, hydroxy,protected hydroxy or together with R₆ forms an oxo; R₇ is hydrogen ortogether with R_(7a) forms an oxo; R_(7a) is hydrogen, halogen,protected hydroxy, —OR₂₈, or together with R₇ forms an oxo; R₉ ishydrogen or together with RF₉ forms an oxo; R_(9a) is hydrogen, hydroxy,protected hydroxy, acyloxy, or together with R₉ forms an oxo; R₁₀ ishydrogen or together with R_(10a) forms an oxo; R_(10a) is hydrogen,—OCOR₂₉, hydroxy, or protected hydroxy, or together with R₁₀ forms anoxo; R₁₄ is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl,hydroxy, protected hydroxy or together with R₁ forms a carbonate;R_(14a) is hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl; R₂₈is hydrogen, acyl, hydroxy protecting group or a functional group whichincreases the solubility of the taxane derivative; R₂₉, R₃₀ and R₃₁ areindependently hydrogen, alkyl, alkenyl, alkynyl, monocyclic aryl ormonocyclic heteroaryl; and the taxane has a structure which differs fromthat of taxol or docetaxel with respect to the C13 side chain and atleast one other substituent.